Only needed for phan, under php8.1 this internal
function is deprecated about null.
The property $subscriptionName is not null when $subscriptionTitle is
not null and current code is safe, but phan cannot see the dependency
between both properties
Change-Id: I9e67309ec25a70c5de91d7f3e8f18447f205a4e4
Unsubscribing was already available from Special:TopicSubscriptions
when JavaScript is disabled.
* Add links to subscribe/unsubscribe in CommentFormatter
* Update links in skin navigation
* Add support for subscribing in the actions
Bug: T321431
Change-Id: If3c4bf7df309d0d98237c3b7b9c129cc2f72cda3